Relation of Vitamin A and “Lard Factor” to Disease Caused by Rancid Lard.

Summary 1. The fatal disease occurring in rats maintained on a purified, vit. A-free diet containing 10% rancid lard (peroxide No. 256) could be prevented by extra feeding of massive doses of synthetic vit. A palmitate or crystalline beta-carotene or cod liver oil. 2. Addition of the distillate fraction of molecularly distilled lard to the diet largely prevented the disease, although this fraction contains only traces of the known forms of vit. A. This “lard factor”, when added to the diet, was more resistant to the action of rancid lard than beta-carotene and vit. A palmitate. 3. Aversion to the diet or improper intestinal fat absorption were not responsible for the results. 4. It was concluded that rancid fats are not toxic per se and that, under natural conditions, the “lard factor” may play an important part in the prevention of the disease ascribed to vit. A deficiency.